Pressure sensors, in particular micromechanical pressure sensors, are used in the area of passenger protection, among other things, in automotive engineering. For example, pressure sensing is often performed on the sides of a vehicle in addition to acceleration sensing in y direction to detect a side impact and to decide whether restraint means are to be deployed. To this end, pressure sensors are located in the vehicle doors; in the steady state, i.e., in the normal state, they detect ambient air pressure p0. This pressure depends on the weather and on the specific elevation above sea level. A side impact which deforms the door of the vehicle is associated with a rapid increase in pressure Δp=p1−p0, which depends on the impact intensity.
As mentioned above, pressure sensors having micromechanical sensor elements are frequently used in practice. Generally, the membrane of such a sensor is diagnosed as being defective only when it is completely destroyed. Minor damage, e.g., scratches on the surface or tears in the membrane, is currently detectable only with additional auxiliary equipment.